kingarthurDone using vocaloid, a synth that uses actual vocal samples. You can get it too sound fairly realistic, but it takes a lot of time and patience and editing.

HarveyjamesI figured they'd patched the emulator to replace the standard synth noise with that vocal clip, and presumably I could download the patch and use it myself in Super Mario Bros and Donkey Kong, but I'm probably wrong.

Westward5 stars for the opening theme alone, which is one of the most epic 8-bit themes ever.